Example 1: Check if a string is numeric public class Numeric { public static void main(String[] args) { String string = "12345.15"; boolean numeric = true; try { Double num = Double.parseDouble(string); } catch (NumberFormatException e) { numeric = false; } if(numeric) System.out....
public static boolean isNumeric(String strNum) { if (strNum == null) { return false; } try { double d = Double.parseDouble(strNum); } catch (NumberFormatException nfe) { return false; } return true; } Let’s see this method in action: ...
您可以使用Apache Commons Lang库中的StringUtils类来判断一个字符串是否为数字。以下是一个示例代码: importorg.apache.commons.lang3.StringUtils;publicclassMain{publicstaticvoidmain(String[] args){Stringstr="12345";if(StringUtils.isNumeric(str)) {System.out.println("The string is numeric"); }else{Syst...
Here is another method from my String utility class. This method uses a regular expression to check if a String is a numeric value. Look at the code, then read through the explanation that follows public static boolean isStringANumber(String str) { String regularExpression = "[-+]?[0-9...
Perhaps the easiest and the most reliable way to check whether a String is numeric or not is by parsing it using Java's built-in methods: Integer.parseInt(String) Float.parseFloat(String) Double.parseDouble(String) Long.parseLong(String) new BigInteger(String) If these methods don't throw an...
StringUtils.isNumeric("12.3") = false Parameters: str - the String to check, may be null Returns: true if only contains digits, and is non-null 上面三种方式中,第二种方式比较灵活。 第一、三种方式只能校验不含负号“-”的数字,即输入一个负数-199,输出结果将是false; ...
String data = "123"; if (DataValidator.isNumeric(data)) { System.out.println("数据是数字"); } else { System.out.println("数据不是数字"); } 复制代码 这样就可以结合Java的isNumeric方法进行数据校验,确保输入的数据符合要求。 0 赞 0 踩最新...
以下是StringUtils.isNumeric方法的源代码: publicstaticbooleanisNumeric(Stringstr){if(StringUtils.isEmpty(str)){returnfalse;}intsz=str.length();for(inti=0;i<sz;i++){if(!Character.isDigit(str.charAt(i))){returnfalse;}}returntrue;} 1. ...
StringUtils.isNumeric("12.3") = false Parameters: str - the String to check, may be null Returns: true if only contains digits, and is non-null 上面三种方式中,第二种方式比较灵活。 第一、三种方式只能校验不含负号“-”的数字,即输入一个负数-199,输出结果将是false; ...
>> check out the course 1. introduction oftentimes while operating upon string s, we need to figure out whether a string is a valid number or not. in this tutorial, we’ll explore multiple ways to detect if the given string is numeric , first using plain java, then regular expressions...